In recent years, a silver halide color photographic light-sensitive material (hereinafter referred to as a color light-sensitive material) is making marked progress in quality of images, and a multilayer structure has come to be used in each of the red-sensitive silver halide emulsion layer, green-sensitive silver halide emulsion layer and blue-sensitive silver halide emulsion layer for much higher image quality and much wider latitude. Such multilayer structure is particularly useful for the improvement of graininess.
Many techniques are known as a means to improve graininess of a color light-sensitive material. For example, British Patent No. 923,045 disclosed a technique to enhance sensitivity without impairing the graininess by distributing couplers of the same color to a high speed emulsion layer and and a low speed emulsion layer, and adjusting the maximum optical density of the high speed layer to a low level. But this technique is not enough to provide a good graininess.
One technique was proposed in Japanese Patent Examined Publication No. 15495/1974, where at least one of the red-sensitive silver halide emulsion layer, green-sensitive silver halide emulsion layer and blue-sensitive silver halide emulsion layer has a sensitivity which decreases in the order of the top layer, intermediate layer and bottom layer, besides maximum optical densities in the top and intermediate layers are set below 0.6. While this technique can noticeably improve the graininess in medium and high density portions, it is liable to cause a high fog density.
Another technique is described in Japanese Patent Open for Public Inspection No. 91945/1987; that is, in a light-sensitive material having at least one emulsion layer of a 3-layered structure consisting of a low speed silver halide emulsion layer, medium speed silver halide emulsion layer and high speed silver halide emulsion layer, setting the maximum optical density in said medium speed silver halide emulsion layer and low speed silver halide emulsion layer to 0.8 or more is proposed for improving the graininess of an insufficiently exposed portion. But this method cannot provide a good graininess in medium and high exposure portions of the green-sensitive silver halide emulsion layer.
Since the green-sensitive silver halide emulsion layer has the highest spectral luminous efficacy among these color-sensitive layers, quality of this layer is one of the key contributing factors to the property of the light-sensitive material. Particularly, deterioration in the graininess of this layer impairs the overall impression of a color image. Therefore, in forming a green-sensitive three-layered silver halide emulsion layer, distribution of silver halide to each of the high speed layer, medium speed layer and low speed layer is very important, and many of the attempts made till now were to use a larger amount of silver halide in high speed and medium speed layers and a less amount in a low speed layer. As a result, problems have come to arise in the graininess in a middle to highlight portion and the latitude in a high exposure portion, thereby it is difficult to obtain a fairly wide latitude by this method.
Moreover, such attempts were to solve overall problems of the graininess in a color light-sensitive material with three-layer structure of layers sensitive to the same color; therefore, it is difficult to attain a high quality image expressible fine texture of human skin by a color light-sensitive material having simply a red-sensitive three-layer structure. To attain this object, there are required much more techniques for proper distribution of silver amount to each of the high speed, medium speed and low speed emulsion layers; setting of an optimum grain size; addition of a coupler capable of forming a slightly-mobile dye, etc. But improvement in gradation of the medium and low speed emulsion layers inevitably increases the amount of a dye forming coupler used in these layers and thereby results in uneven graininess, losing capability of expressing delicacy of the skin texture.
Further, the distribution of silver to the medium speed layer (the medium layer) and the low speed layer (the lower layer) in a larger amount than that to the high speed emulsion layer (the upper layer) causes troubles such as silver retention in a red-sensitive layer in a rapid process because the red-sensitive layer is the closest to the support.
Taking notice of the above conditions, the present inventor has studied how to improve the graininess in both of the green-sensitive silver halide emulsion layer and the red-sensitive silver halide emulsion layer and found that an excellent graininess, a wide latitude in a high exposure portion of the green-sensitive layer, and an improved storage stability of the red-sensitive layer, as well as a good aptitude for rapid processing of the light-sensitive material can be attained by prescribing the order of arrangement of the high speed, medium speed and low speed emulsion layers in the three-layered structure and the amount of silver used in these emulsion layers.